Variation of the Kuroshio cold eddy.

Abstract

Variations of the internal structure of the Kuroshio cold eddy associated with the large meander of the Kuroshio, and its correlation with the external features of the eddy from 1975 to 1980, are investigated. Vertically averaged values of temperature, salinity and dissolved oxygen content are used to describe the internal structure of the eddy, the position of the center of the cold eddy, and the area of the eddy region was used as parameters of the external features of the eddy. The investigation revealed the following items. The temperature in the deep layer ( 1000-2500 m) in the central area of the cold eddy, increased most of the time in the meander period, but showed an intermittent decrease from time to time. This intermittent decrease of temperature may be a cause for long-period staying of the cold eddy and the Kuroshio meander. The temperature in other layers (upper 200-500 m, intermediate, 500 1000 m) has not varied in phase with the temperature of the deep layer. In the decaying and disappearing stage of the Kuroshio meander, a conspicuous increase in temperature is observed in the deep layer. Along with this temperature increase, the water characteristics themselves also changed in the whole area south of Japan (the increase in salinity and dissolved oxygen content).